Rapid determination of time-resolved fluoroimmunoassay for medroxyprogesterone acetate residues in pork tissues and comparison with liquid chromatography and tandem mass spectrometry.

A competitive time-resolved fluoroimmunoassay (TR-FIA) was developed for the determination of medroxyprogesterone acetate (MPA) residues in pork tissues. The limits of detection (LOD) was determined to be 0.06 ng g-1 and the limits of quantification (LOQ) was less than 0.8 ng g-1. The intra-assay variations were below 10% and the interassay variations ranged between 9.7 and 12.7%. The mean recoveries established at six concentration levels varied from 87.3 to 108.3%. The results obtained by the TR-FIA and ELISA showed a good correlation. The established TR-FIA was validated for the determination of incurred pork tissues and confirmed by high-performance liquid chromatography and tandem mass spectrometry (LC-MS-MS). This proposed technique could be applied to routine residue analysis.